1. Field of the Invention
This invention relates to closure devices and more particularly to a clasp for releasably securing the opening to a container, such as a purse, a jewelry box, a suitcase, or a file for documents or collectibles. Taken in a somewhat broader aspect, the invention has potential applicability to the closure of larger containers, such as cupboards, mailboxes, cabinets, and even rooms, where the opening requiring closure takes the form of a window or door.
2. Background Art
Many approaches have been used to effect the secure closure of both small and large containers, such as those described above. One approach has involved the use of a fixed member or catch on one side of the opening to be secured and a moveable latch opposite thereto on the other side of the opening. Typically, the latch, which is rotatable in a plane parallel the outer surface of the container, is designed to pierce or seize the catch in order to effect the desired closure. In some instances, the latch includes complicated camming mechanisms which act upon the catch once captured and draw tightly closed the opposite edges of the opening involved.
In such known closure mechanisms, the rotation required of the latch to effect capture of the catch is in a single predetermined angular direction of rotation. This then necessitates a degree of experience with the clasping mechanism in order for a user to routinely operate the mechanism in an automatic manner.
When closure is effected in such closure mechanisms, the catch and the elements of the latch that seize it remain in an exposed condition. This can have a displeasing aesthetic consequence. Functionally, however, such exposed components tend to snag on other articles causing damage and risking the inadvertent unclasping of the closure mechanism. Where catch and latch are installed in opposed recesses in the mating edges of the opening to a container, the catch and latch may be concealed, but the complexity of the mechanism and its installation are substantially increased.
Typically, rotatable closure mechanisms of the type referred to employ protruding tabs, thumbpieces, spurs, and levers on the rotatable member. While these elements may enhance the ease by which an operator closes and opens the mechanism, they are features which increase the possibility of an unwanted release of the mechanism due to a chance impact or to snagging. To reduce the chances of this type of release, it is frequently necessary that the rotatable latch be made stiff to rotate, particularly in its closed position. Unhappily, such a solution to the problem of inadvertent releases only results in a mechanism which requires a significant threshold of force for its successful operation.
It is toward this end that a camming action is often incorporated into the rotatable latch. This is undertaken, however, at some cost to the simplicity of the structure of the latch and its ease of mounting to the container to be closed thereby.